H2, HD, and CO at the edge of 30 Dor in the LMC: the line of sight to Sk-69 246
Abstract
FUSE and IUE observations of Sk -69 246, a WN 6 star to the north of 30 Dor, reveal the existence of LMC interstellar gas in at least 3 velocity components.In one of these components FUSE spectra show strong absorption by molecular hydrogen with a column density of log N(H2)=19.6. We investigate the physical conditions in this cloud, which is probably located near the H II region surrounding Sk -69 246. HD and CO with column densities of about 13.9 and 13.0 dex, respectively, are detected. The N(CO)-to-N(H2) ratio is consistent with values found in the Galaxy. From the population of the rotational levels of H2 we derive a gas temperature of 72 K and a radiation field U=3*10-15 erg/(s*cm3) at 1000 nm. The fractional abundance f=2N(H2)/[N(H I)+2N(H2)] is approximately 0.07, rather high for an E(B-V)<0.1.
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